 He was author of a textbook titled "Die Geisteskrankheiten des Kindesalters" (Mental Diseases of Childhood), a book that reportedly was the first systematic work on child psychiatry in Germany.He also penned "Psychiatrie für Ärzte und Studirende", a textbook that was published in four editions between 1894 and 1911.In his writings, Ziehen is credited with introducing the terms "affective psychosis" and "psychopathic constitution".